Homeostasis

Question 1

Systems that interact with the external environment and expand energy

Answer 1

Nervous system
locomotor system
reproductve system

Question 2

Systems that interact with the internal environment, and help to achieve homeostasis:​

Answer 2

Cardiovascular, respiratory, excretory, alimentary​

Question 3

Systems that control others systems​

Answer 3

Nervous system, endocrine system ​

Question 4

why does homeostasis occur

Answer 4

to correct any changes in the cellular environment

Question 5

When do cells function most effectively

Answer 5

under optimum conditions

Question 6

what is the negative feedback system

Answer 6

A change in a variable activates mechanisms that alter the level of that variable so as to counteract the change​
Tends to maintain the status quo​

Widely used in many physiological control systems​

Question 7

What are the two mechanisms of homeostasis

Answer 7

Feed-back control
Feed-forward control

Question 8

Negative feedback steps

Answer 8

Variable-sensor-signal-control centre-effector

EXAMPLE:
Core body temp-Hypothalamus receptors-Send signal to hypothalamus-muscle increase heat production while skin reduces heat loss to in turn increases the body temp to restore the normal.

Question 9

What is the feedforward control

Answer 9

This involves altering a behaviour before there is an obvious ‘error signal’

Anticipatory action:
-stop eating before ‘full’
-Increasing heart rate, ventilation at onset of exercise
-Probably learned behaviour

Question 10

What is the positive feedback system

Answer 10

A change in a variable activates mechanisms that alter the level of that variable so as to increase the change (a small change activates a much larger one)
Used in blood clotting, childbirth, action potentials

NOT USED IN HOMEOSTATIC CONTROL

Question 11

Extracellular fluids:

Answer 11

interstitial fluid - 11 ltrs
plasma - 3 ltrs

Question 12

Intracellular fluids:

Answer 12

28 ltrs
water and ions can move between both ECF and ICF

Question 13

Osmosis

Answer 13

Water movement occurs by osmosis, and you will see some examples of this in the laboratory​

Osmosis is simply diffusion of water along its concentration gradient​

You can also use these diagrams to work out what happens when someone drinks (or loses) fluids of different composition​

Question 14

Homeostasis keeps every variable constant all the time: True or False

Answer 14

False:
This is because there is some delay in operating the control systems​

Also, each particular variable is not maintained at the same value in different individuals​

There is a range of values which is considered ‘normal’​